Apparatus for progressive heat treatment



y 1940. F. s. DENNEEYN ET AL 2,202,758

APPARATUS FOR PROGRESSIVE HEAT TREATMENT Original Filed Sept. 24, 1934 3Sheets-Sheet l I as v INVENTORS y 28, 1940- F. s. DENNEEN ET AL2,202,758

APPARATUS FOR PROGRESSIVE HEAT TREATMENT Original Filed Sept. 24, 1934 3Sheets-Sheet 2 35 5 3 K 55% s&% 5 I J I I 3 Z 4 /IIIIIIIIIIIIIIIIIIII'/Z5 z INVENTORS jg%%azaaJda iawwzba m V. Y L.

May 28, 1940. F. s. DENNEEN El AL 2,202,758

APPARATUS FOR PROGRESSIVE HEAT TREATMENT Original Filed Sept. 24, 1934 3Sheets-Sheet 3 III? g /42 III/ /A {w M Patented May 28, 1940 UNITEDSTATES PATENT OFFICE APPARATUS FOR PROGRESSIVE HEAT TREATMENTcorporation of Ohio Application September 24, 1934, Serial No. 745,194Renewed November 9, 1938 29 Claims.

The present invention, as a further improvement on that shown anddescribed in our copending application Serial 689,904, relates, asindicated to apparatus for progressive heattreatment, and illustratesone form of apparatus suitable for following the method and producingthe article described and claimed in our application Serial No. 745,195entitled Progressively heat-treated article and method of producing samebeing filed even date herewith. This invention is particularly useful inthe heat-treatment of large metal parts of cylindrical or of modifiedcylindrical form such as rolls, shafting and tubing and of special formsof beams, rails and other articles in which the portion desired to beheat-treated is either too large or too irregular in form to be treatedin its entirety in a single momentary operation without change ofposition of the heating element with respect to the work.

In general, the means and method described herein for the practice ofour invention pertain to the progressive heat-treatment of a part, orparts, of an article by heating, quenching, and 5 tempering, and offerparticular advantages in the surface zone hardening of such articles asshafts, mill rolls, and the like. While the preferred means and methodof heating, which is one of the principal steps in our process, depend30 upon induction heating accomplished through the use of a heatingelement spaced from the article and supplied with alternating currentsof relatively high frequency, we have shown and described other meansand methods of heating that 35 may be satisfactorily used. We havefurther pointed out various uses for our invention whereby differentresults may be obtained and on articles of various shapes and made fromvarious materials.

40 In heat-treatments there have been no teachings providing for aprogressive heating and quenching of such articles which do not changethe chemical composition of the metal being treated, or leave untreatedareas or imperfectly 45 treated areas, or disturb physical qualitiesalready provided in portions adjacent to those areas desired to beheat-treated.

It is to be understood that the heat-treatments described in thisspecification will apply to a wide range of metals other than ferrousmetals and that the results may be of a widely varying nature, butreadily controlled by the apparatus employed and the various possiblemethods of its use.

Heretofore, when cylindrical articles were heattreated, such as forsurface hardening or surface annealing, it was necessary to heat allparts of the entire surface substantially simultaneously and to quenchlikewise by a process applying simultaneously to all parts heated,otherwise Ii there would be laps or joints in which the hardness woulddiffer from that of the remainder of the area heat-treated. In case oflarge articles, this required large and expensive apparatus, and

a heavy consumption of power and usually pro- 10 duced irregular andunsatisfactory results. This was particularly true in the treatment ofcylindrical pieces having a step or shoulder and in which it was desiredto heat-treat the cylindrical surface to, but not into, the region ofthe shoulder.

Furthermore, the treatment of tapered or otherwise modified portions ofan article would require specially formed heaters or heating elementswhich would be diflicult to adapt to other 20 portions of the articleand would require special quenching means as well. There has been,heretofore, no automatic means for progressively changing the form ofheating or quenching elements in passing from one part of the article toanother.

In addition, in changing from one portion of the article to another, thepower required usually changes, due to a change in the amount of metalexposed to the heating effect. In applications heretofore used, thischange required more or less complicated adjustments in the variouscircuits pertaining to the supply source of the heating current.Further, no means has heretofore been provided for distributing thenecessary power output between two or more elements heating differentparts of the article simultaneously. As has been pointed out inco-pending application Serial No. 718,003, it is highly important inzone hardening the surface of a steel article that the heating of thezone to the correct temperature for quenching'be accomplished at so higha rate that there will be insuflicient time for the heat to travelappreciably beyond the zone to be hardened. Further, the quenching mustbe vigorous and must be accomplished immediately when the zone hasreached the proper temperature and the cooling accomplished almostinstantaneously. Only in this way is it possible to obtain a strongintimate bond area between the hardened zone and the core, for if highrate 01. heating and of cooling are not accomplished, appreciablequantities of free ferrite will form in the bonding area greatlyinjuring the strength of the bond. Another important need for high rateof heating and quenching is that with slower heating the heat penetratesa considerable distance beyond the zone to he hardened, snakingimmediate quenching impossible due to the thickness of the layer throughwhich the heat must be removed and, too, where substantially all of theheat cannot be immediately removed in the quench the heat in the areasremoved from the zone will travel back into a part of the zone wherehardening has already been accomplished, tempering or softening thatpart of the zone, thereby undoing a part of the hardening that had beenaccomplished. In our invention we have provided means and method foraccomplishing both the desired high rate of heating and high rate ofcooling. I

This invention has for its chief object the provision of apparatuswhereby an article may be progressively heat-treated. Another object ofthis invention is to provide means for controlling a progressive methodof heat-treatment whereby a region adjacent to a shoulder of an articlemay be treated in uniformity with other parts of the treated surface. Afurther object is to provide means for progressively and simultaneouslyboth hardening and tempering an article. An additional object is toprovide means for uniformly distributing heat over an article of varyingform thus progressively being heat-treated. A still further object is toprovide means for automatically varying the position of heating elementsduring the heating interval. Another object is to provide means forprogressively transferring the heating effect and in varying amount fromone heating element to another and thus to transfer the heating effectfrom one part of the article to another.

With these and other objects in view which will appear as thedescription proceeds, said invention then consists of the apparatushereinafter explained and the method of use of this apparatus and suchmodifications of them as will produce the results described. We desireto have it understood that the invention is not limited to the detailsof construction and arrangement of parts illustrated in the accompanyingdrawings as the invention is capable of many other embodiments, and thephras'eology employed is for the purpose of description and not forlimitations.

In said annexed drawings:

Fig. 1 is a diagrammatic elevation partly in section showing theelements of our improvement applied to a plain cylindrical object. Fig.2 is a view in the direction indicated at section 2-2 of Fig. 1. Fig. 3is a diagrammatic elevation similar to Fig. l but showing modifiedparts. Fig. 4 is an elevation similar to Fig. 3 but of a still furthermodification. Fig. 5 is an elevation, partly in section, showing thegeneral arrangement of an automatic means for heat-treating a steppedcylinder. Fig. 6 is a section on line 66 of Fig. 5. Fig. 7 is a sectionsimilar to Fig. 6 but showing a modified form of heater. Fig. 8 is aview similar to Fig. 3 but showing an alternative heating means. showingan alternative quenching means. Fig. 10 is a section on an enlargedscale of the upper heating element. Mg. 111 shows a modification of thedevice illustrated in Fig. 4. Mg. 12 shows a modification of theapparatus adaptable to the heat treatment of pipes or tubes.

In Fig. 1 the cylindrical article it to be treated is supported thecable or red ii and eye it in such a Way as to he lowered at at anyether d si ed rate.

more tide Fig. 9 is a view similar to Fig. 3 but Fears i3 definitelysecured in place are employed as means for guiding the direction of thecylinder in its movement. the arms 86 and il serving as. intermediatemembers for holding the cylinder in definite position relative to theguide bar and sliding thereon. The cylinder is provided with anextension I! serving as a guide bearing and the shank I! of the eye l2serves as a guide hearing at the opposite end of the cylinder. Thesebearings, being in alignment, permit the cylinder to rotate when arotating or oscillating motion is given to the supporting cable or rodll.

Secured to the guide bar, or to some other part of the structurecarrying the guide bar, are the heating and quenching elements. Whencorrectly arranged relative to each other and to the article to beheat-treated, and supplied with the correct amount of heating energy andrefrigerant, these being supplied at the proper time and rate for thearticle being heat-treated, this device will produce almost any desiredheat-treatment consistent with the material of the article.

In operating the device shown in Fig. 1, and assuming it is desired toheat-treat the surface of the cylindrical article shown for its entirelength, the lower end of the article is first brought to a line abovethe heating element I8 and the article is then lowered or passed for itsfull length through the entire series of heating and quenching elements.The heating element It ordinarily is supplied with low frequency currentand serves as a pre-heating means only for the surface metal of thecylinder as it enters the group of heating and quenching elements. Undermany conditions, however, the use of the pre-heating element may beentirely dispensed with. The portion of tlie surface thus pre-heatedenters the preferably water cooled heating element I9 which ispreferably supplied with current having a frequency appreciably higherthan 60 cycles so com monly used in electrical supply circuits and isbrought to a relatively high temperature before this surface emergesfrom this last element. The portion of the surface thus heated passesthe insulating shield 20 and then enters the annular quenching ring 2|from which quenching fluid is projected vigorously onto the heatedsurface through orifices 22 which are directed in any suitable way tohelp prevent the fluid from rising upwardly and passing the edge of theshield 20.

As the cylinder continues to move downwardly the quenched portion passesthe shield ring 23 and enters the heating element 24 which reheats thesurface to any desired degree after which it is permitted to cool in theair or any other atmosphere. This, in the case of a ferrous material,tempers the surface hardened by the preceding heating and quenching. Theshank I! of the supporting eye is made of sufficient length to permitthe upper edge of the cylinder to pass completely through the temperingring 24 before arm i4 reaches heating element l8.

The foregoing procedure is particularly applicable in the case of anarticle made of steel having a carbon content of approximately .35 ormore and will produce a surface zone of substantially uniform hardnessand substantially free from objectionable strains that may have been setup during the hardening process and substantially free from certainother strains that may have existed prior to hardening.

Articles made from a Wide variety of different materials includingmetallic as well as non-metallic, react diiferentiy when subjected tothis presses. For instance, co seer, brass, or bronze articles may beappreciably softened or annealed by the heating and subsequent quenchingherein described. Depending upon the material in the article and theresults desired to be obtained, the use of either the pre-heatingelement I. or the tempering element 24 or both of these may be omitted.

When it is desired to heat-treat a shaft having a shoulder asillustrated in Fig. 3, a somewhat different arrangement of heatingelements or heaters is desirable. In this figure the actuating andguiding means for the cylinder are not shown but may be made similar tothose illustrated in Fig. 1.

- In the device shown in Fig. 3 the upper heater 25 is so formed at 26as to reduce as much as possible the heating of the face 21 of theshoulder when this shoulder comes into its position of closest proximitywith this heater. This heater has an inner annular chamber 28 and anouter annular chamber 29. The inner chamber carries quenching fluid andthe inner annular wall has perforations 30 for projecting this fluidonto the walls of the cylindrical articles 3|. The outer annular chamber29 serves as a cooling jacket for the heater itself.

Below heater 25, but separated from it by insulating ring 33, is theheater 34. Immediately below heater 34 is the insulating shield ring 35which also serves as a spacer for the annular quenching ring 36. As bothheaters 25 and 34 supply heat simultaneously for the surface of thecylinder 3| the heating of this surface progresses as the cylinder 3| ismoved relative to the heaters, the surface temperature of the cylinderbeing least at the entrance to the upper heater and being greatestadjacent to the shield ring 35. By regulating the relative inputs ofenergyto the two heaters at the time shoulder 21 reaches its limitingposition relative to heater 25, the rate of heating of heater 34 isreduced and that of heater 25 is increased so that for a short intervalafter the cylinder 3| has stopped in its axial movement, the heating isdistributed substantially evenly over the surface enclosed by theheaters. At the termination of this heating interval, quenching liquidis projected onto this surface. usually through orifices such as 30 andthe entire convex surface is thus heated and quenched to producesubstantially uniform physical properties. Fig. 10 illustrates means forusing chamber 28 as a cooling jacket. In this the annular space 28'carries the cooling and quenching fluid which, during the heating andidle intervals, is filled with this fluid circulating under relativelylow pressure. At the instant quenching is required, this pressure issuddenly increased by any suitable means and valves 30' which may benumerous and assume a variety of forms, and which are held closednormally by resilient means such as spring 29', quickly open, sprayinglarge quan tities of quench onto the heated surface of the cylinder 3|and cooling it very suddenly. It will be evident that the heater 34 maybe omitted and approximately the same results will be obtained.

For the purpose of automatically regulating the heating as this heatingprogressively approaches the shoulder of a shaft or other cylindricalform, the heating elements or heaters may be made in the form of aflexible and variable helix as shown at 38 in Fig. 4. Suitable currentis supplied at the terminals 39 and 40. This helical conductor issupported by the quenching ring 4|, suitable insulation being employedas at 42. As the cylindrical article 43 passes into this helix it isheated by the coils and as it emerges is quenched by the fluid from ring4|. When shoulder 44 engages the upper part of the helix throughinsulation 45, the helix is compressed and more and more heat! ing isconcentrated adjacent to the shoulder causing the depth of heating tobecome equalized. At the time the spaced coils reach a substantiallyclosed relationship the heating is completed. All the heated surfaceabove the ring 4| is then quenched rapidly and uniformly by a suddenincrease of pressure within the hollow conductors causing a joint lineextending along the inner part of the helix at 4| of Fig. 11 to open bywall deflection as indicated by the broken lines at 4|" along its entirelength and quickly flooding all the surface of the cylinder stillremaining unquenched. As an alternative or supplemental quenching means,a system of nozzles as at 42' of Fig. 11 may be arranged to projectstreams of quenching fluid through the helical space between the coilsand onto the heated surface, the quench being supplied by a series ofcircumferentially spaced headers 43" fed by piping such as 44'.

As it is frequently desired to heat treat cylindrical articles havingtapered portions or portions of a modified form and to apply thisheattreatment to large quantities of these articles, an automaticheating and quenching mechanism is desirable. Such a mechanism is shownin Fig. 5. In this mechanism, the cylinder 46 to be heat-treated issecured to the screw shaft 41 so as to be suspended thereby and torotate therewith. The lower end of the cylinder is centered as at 48 toinsure against any irregular or eccentric movements. At the upper end ofthe screw shaft and secured thereto is the gear 49. Meshing with gear 49is the gear 50 having a face of sufflcient width to permit itsengagement with gear 49 through the latters entire range of axialmovement. Gear 50 is carried on shaft 5| which has worm wheel 52 keyedthereto. The worm 53 meshes with worm wheel 52 and is driven by a motor(not shown) carried on the frame of the machine. Screw shaft 41 engagessleeve 54 which is provided with external screw threads to engage themetal of theframe of the machine at 55 as well as with internal threadsto engage the shaft 41. The leads of the internal and external threadsof sleeve 54 are' different so as to produce different rates of axialmovement of the cylinder depending on whether sleeve 54 is heldstationary by a friction brake 54' engaging the radial flange thereof asshown or whether the stop pin 55 has engaged the sleeve and has causedit to rotate with the shaft, thereby overcoming the resistance of thebrake. Stop pin 56 may be moved to another position as at 55 to changethe position where a different rate of axial movement starts.

As the motor driven gearing, above described, causes the screw shaft 41carrying the cylinder 46 to descend, the yoke 51 secured to the guidebar 58 and in engagement with the annular groove provided by the collar59 at the lower end of screw shaft 41, causes this guide bar to descendwith the cylinder and through the stock 60 carried at the lower end ofthis bar maintains the center 5| in engagement with the cylinder at 48thus insuring concentric axial movement of the cylinder.

Supported in the lower part of the machine by guide block 52 carried onthe frame 53 of the machine are the heaters 64 and 55. Each of theseheaters is made up in sections as shown at 65, 61 and 68 of Fig. 6. Theguide bar 58 maintains the section 66 in correct location and other alsoof rectangular section prevent the heater sections from rotating andthus cause them to have only a radial movement relative to the cylinder.These guide bars are insulated from the heaters and are provided withpressure blocks l2 and guided springs it for maintaining the heaters incontact with the keys or cams. Each of the heater sections has a portionit formed to properly engage its controlling cam or key.

The heater sections 6E5, 671 and 88 are provided with interengagingportions at if and it to insure a substantially continuous form and withflexible conductors at ll and ill. The inner contours of the sections asat l9 are made to approximate the average form of the tapered orotherwise formed portion of the cylinder so that the heating will besubstantially uniform around its periphery, the rotation of the cylinderduring the heating interval compensating for any lack of uniformitywhich. may otherwise be present.

In the modification shown in Fig. 7 the heater is a single loop whichmay be made in numerous ways, either from a single piece of material orin composite form as shown. The inner portion 8d which may be a.laminated member conducts current in close heating relationship to thecylinder 46 and theouter supporting element 8i which may serve as-acooling jacket is made of varying radial thickness so that the heater.as a whole, in opening and closing through a reasonable range; willmaintain a. substantially circular interior form thus making it'possibleto provide for a uniform air gap and uniform heating, even if thecylinder were not rotated during the heating interval. To maintain auniform gap as the heater opens and closes, this opening and closing isdefinitely controlled by guide bars 82 and 83 similar to' guide bars 58,69 and HI and which are likewise provided with cam members such as 85and 85. In this construction the guide bars are Provided with a limitedamount of rotative freedom for purpose of self alignment. Springs 86and'.-spring seats 81 are provided similar to the construction shown inFig. 6 for maintaining contact with the cams. Both the heaters shown inFigs. 6 and 7 may be made in multiple as shown at 64 and 65 of Fig. 5 oras shown in Figs. 1 and 3, the guide bars and cams being arranged tocontrol each heater separately.

Means for supplying cooling and quenching fluid are illustrated in Fig.5. Fluid for the lower heater is supplied from pipe 88 through valve 89and pipe 80. Similarly, fluid from pipe 9i through valve 92 and pipe 93is supplied to the upper heater. In this construction, the extension 94on the stock 68 engages the arms 95 and 96 of the valves as the stockmoves downward during operation thus first closing valve 89 andsubsequently opening valve 32 after the shoulder 91 of the cylinder hasapproached closely enough to heater ill and the surface of the cylinderadja= cent to the shoulder has been suihciently heated.

As indicated in Fig. 5, current is supplied to the heaters hy conductorslid and 9E] connected FIX ltl

lilli secured to a suitable frame till. The axial movement of theprimary readily controls the flux threading through the two or moreparallel single turn elements of the secondary and thus controls thecurrent and power output of these elements. By the upward movement ofthis primary coil, the current delivered to the lower heater 65 may bereduced and that delivered to upper heater increased. By a sunlcientmove ment of this primary, currentfrom coil llli may be reducedsubstantially to zero and this move= ment of the primary coil thusmay-be used to en= ergize or de-energize one or the other of thesecondary circuits. By this means a very convenient and rapid change incurrent in heaters 64 and 85 is accomplished without arcing and withoutany serious disturbances in the cir-= cuits, thus making it possible toincrease the rate of heating from heater 64 as this heater is approachedby the shoulder 9'5 and simultaneously reducing the heating effect ofheater 65 thus making a uniform heating and quenching of the entirecylindrical and conical part of the work possible. By varying thespacing of the coils in the primary member of the transformer a widevariation in the energy delivered by the secondary member may beaccomplished.

For the purpose of making the operation of this transformer controlautomatic, arm I85 which. is hinged at 8 on a bracket I89 on the frameof the machine is engaged by the end ll of the yoke 51 .as the work islowered and thus raises the primary coils I02 at the desired rate. 'Bymaking the end ill of arm I05 adjustable or by providing adjustments onthe end it of the yoke, the timing and rate of movement of the primarycoils and the resulting secondary currents are accurately andconveniently controlled.

Variations in the form and extent of the areas to be hardened on article46 may require controls more accurate and capable of more sensitiveregulation than those provided by the movement of the primary coil I02.To the accomplishment of this, an automatic control which regulates thetotal energy delivered to the primary is provided. This comprises thecam H2 replaceably and adjustably carried on shaft H3. Shaft H3 isdriven by gear H4, this gear being actuated by the rack H5 integral withor secured to the guide bar 58 which moves at the same rate as the workbeing hardened. The rotation of cam i ii actuates the plunger M6 in thecarrier bracket 0 ll, compressing the return spring i it and causing rodH9 to rotate lever E20, this lever being carried by shaft i2l. As thelever ltd is moved by action of the cam it'd, the lever end 522 contactswith the rheostat resistance 823, van'irig and corrtrolling the currentdelivered by the exciter it"! to the generator field H25, therebycontrolling the output of the generator 025 which supplies the energy tothe leads ltd and tilt of the primary coil m2. lit will he understoodthat the cam it would he so shaped and timed that the energy deliveredto the heating elements would be varied and controlled so as to maintainthe correct rate and intensity of heating even though the dimensions or.form of -the surface being heated be constantly changing.

In some, applications of this apparatus, it may be found desirable toenclose the mechanism or certain parts of it. In this event the frame ofthemachine will be extended as indicated by broken lines at I26. It willbe understood that this may enclose the transformer and the heaters aswell as the other parts of the mechanism. When a full enclosure isemployed, an opening is provided for retracting the work and itssupporting structure, such opening being closed during operation by thecover indicated by broken lines at I26 In some instances where electricenergy of suitable character is not available for heating the article,combustion means may be employed as illustrated in Fig. 8. In thisconstruction an annular burner I2! preferably water cooled, and havingsuitable mixing nozzles I28, surrounds the article I29 to beheat-treated, This burner may consist of a series of individual nozzleseither fixed as at I33 or adjustable as at I28, or the burner may have arelatively thin continuous aperture all the way around, that willproduce a sort of ribbon form heating flame extending completely aroundthe article. Fuel, which may be a gas, a liquid, or a finely dividedsolid, is introduced through the space I30 within the burner and theflame is projected with considerable intensity against a relativelynarrow zone of the article. The shield I3I of heat resisting materialserves as a means of limiting the downward projection of the flame. Asthe heated zone passes downwardly past the shield I3I it enters thespace within the ring type quenching manifold I32 from which coolingfluid is projected vigorously and continuously onto the heated surfaceduring the time the article is traveling through this manifold. Undercertain conditions it may be desirable to rotate the article I29 inaddition to traversing it through the heating and quenching elements.

In Fig. 9 the article I34 is progressively heated as it passes theheater I35 and the surface zone is quenched and hardened as the heatedarticle is lowered into the tank I36 containing quenching medium I31, adeflector I38 serving to aid in preventing the quenching medium frominterfering with the heating.

The processes herein described have further advantage over otherprocesses in that the heating is so rapid and by the use of sufficientlyhigh frequency in the electric supply source may be confined to soshallow a zone that the heated zone may be quenched and cooled almostinstantaneously so that with the use of steel of the proper analysis andcharacteristics, practically any desired degree of hardness may beobtained. Further, the heating and cooling is accomplished at so high arate that practically no free ferrite forms in the bond area between thehardened zone and the core, thus obtaining maximum strength and insuringagainst fracture or breakage of the hardened zone. It is well known thatwhen an article has been hardened by heating and immediate and thoroughquenching so as to produce extreme hardness, severe strains are set upwhich, if not properly relieved by tempering or drawing, result inchecks or cracks that gradually increase, spoiling the surface and oftenresulting in complete fractureof the piece. The detrimental effectsresulting from the strains set up in hardening an article increasegreatly as time elapses between the hardening and drawing operations. Itthe drawing is properly done immediately after hardening, thedetrimental effects of the hardening strains become practicallynegligible.

In our process we have provided means whereby this annealing may bequickly and economically accomplished immediately after the article hasbeen hardened, the drawing action taking place progressively andimmediately following the hardening, thereby practically nullifyingdetrimental effects that would otherwise result from hardening strains.

'While the apparatus illustrated in the accompanying drawings is shownas arranged for heat treating exterior surfaces of articles, simplemodiflcations may be made whereby selected portions of interior walls inholes or recesses may be heat treated. For instance, the inside wall ofa pipe or tube may be progressively heat treated by heating from withinwith an open ring type heater supplied with current from an alternatingcurrent source and arranged to deliver heating energy to the inner wallof the pipe, the heater and pipe being moved with respect to each otherand a quenching fluid being discharged against the heated area.

Another modification in heat treating an article such as a pipe or tubewould be to heat through the wall from an externally placed ring typeheater as shown at I39, Fig. 12 and to quench the inside wall as it isheated to the proper temperature by projecting quenching fluid fromnozzles I40 in spray head I42 which is supplied by piping I43 and I44,relative movement between the tube and the heating unit being providedfor, so that the heat treating may be progressive.

Obviously, in the case of a bar or tube the article could be heattreated all the way through and progressively by heating and quenchingfrom the outside or by heating from one side and quenching from theother.

Other modes of applying the principle of our invention may be employedinstead of the ones explained, change being made as regard the meansherein disclosed, provided those stated by any of the following claimsor their equivalents be employed.

We, therefore, particularly point out and distinctly claim as ourinvention:

1. In a device for heat treating, a substantially annular currentconductor serving as a heating element, the heating element embracing apart of an article to be heat treated, quenching means within saidheating element, a second heating element, means for causing relativemovement progressively between the aforesaid article and said heatingelements during a heating interval, and cam means extending axiallythrough a part of each heater for progressively changing the form of theheater.

2. In a device for heat treating, a. conductor in heating relationshipwith an article to be heat treated, said conductor comprising relativelymoveable members, means for causing relative movement between saidmembers during a heating interval, and means whereby said relativemovement causes the conductor to be varied in form during said heatinginterval to substantially conform with a varying form of the article.

3. In a device for heat treating, a conductor in heating relationshipwith an article to be heat treated, said conductor comprising relativelymoveable members, means for causing relative treated, said conductorcomprising a series of substantially rigid connected members, means forproducing relative movement between said members and said article, meansfor movingv said members relatively to each other during a heatinginterval, said last named means being controlled by mechanism operatingcoincidentally with the relative movement of the article and the con-'ductor.

5. In a device for heat treating, a plurality of conductors in heatingrelationship with an article to be heated, said conductors being inseries and forming a loop surrounding the article, means for causingrelative movement between said article and said conductors during aheating interval, means for relativelymoving the conductors to changethe loopduring the heating interval, and means for progressively varyingthe current in one of said conductors, said last named meansbeinginterconnected with the means for causing the relative movement. 1

6. In a device for heat treating, a conductor in heating relationshipwith an article to be heated, means for producing relative movementbetween said article and said conductor during a heating interval, andcam means for progressively varying the current in one of saidconductors to correspond with variations in the relative positions ofthe conductor and article, said last named means beingactuatedcoincidentally with the relative movement between said articleand said conductor, the relative. movement being produced by an axiallyextending sliding cam having driving connection withzthe aforesaid cammeans.

7. In a devicelfor heat treating, a. conductor in heating relationshipwith an article to be heated, automatic means for causing relativemovement between said article and said conductor at different ratesduring a heating interval in accord with a pre-determined ratio, meansfor varying the current in said conductor during the heating interval,and quenching means.

8. In apparatus of the character described, a conductor embracing a partof an article to be heated, a support for said article, said supportcomprising a threaded stem attached to' the article, said stem servingas means for simultaneously rotating the article and advancing thearticle thru the conductor, means for supplying heating current to theconductor, and means associated with the advancing means for controllingthe heating current.

9. In apparatus of the character described for heat treating an article,conductors surrounding said article, the, conductors being insubstantially parallel spaced relationship, each conductor beingcomposed of relatively movable parts, means for moving the articlerelative to the con ductors whereby the article passes successivelythrough the conductors, means interconnected with the moving means formoving the relatively moveable parts of one of the conductors while thearticle is being moved relative thereto, passages in the conductor forprojecting a quenching fluid onto said article, and valve means forcontrolling the flow of quenching fluid, the valve with the moving meansfor controlling a flow of current in the secondary of the transformer.

11. In apparatus of the character described, a substantially annularinductor extending circumferentially around a cylindrical article to beheat treated, said article being of varying diameter,

I means for rotating said article while passing it axially through theinductor, the inductor having a jacket for acooling fluid, axiallyextending cams slidable in said inductor for modifying the diameter-ofthe annular inductor to maintain a substantially uniform space betweenthe article and the inductor, and means for controlling current beingdelivered to the'inductor.

12. In apparatus of the character described, a conductor extendingperipherally around an article to be heat treated, means forprogressively moving the article thru the conductor, an axiallyextending cam moving with the article, said cam displaceably engaging apart of the conductor for moving said part of the conductor transverselyrelative to the direction of motion of the article, and means movingwith said article for operating a valve controlling a flow of coolingfluid.

13. In apparatus of the character described, a conductor extendingperipherally around an article to be heat treated, a transformersupplying current to said conductor, means for progressively moving thearticle thru the conductor, an axially extending cam moving with thearticle, said cam displaceably engaging a part of the conductor, andmeans movingwith the article for relatively moving the primary andsecondary coils of the transformer whereby current in the conductor isregulated.

14. In apparatus of the character described, a conductor extendingperipherally around an article to be heat treated, a transformersupplying current to said conductor, means for progressively moving thearticle thru. the conductor, an axially extending member moving with thearticle and displaceably engaging said conductor, means moving with thearticle for relatively moving the primary and secondary coils of thetransformer whereby current in the conductor is reduced, and meansmoving with the aforesaid axially extendingmember for controlling a.supply of cooling fluid to said conductor.

15. In apparatus of the characterdescribed. a conductor extendingperipherally around an article to be heat treated, a transformersupplying current to said conductor, supports at opposite ends of thearticle, means moving said supports whereby said article passes thru theconductor, means associated with said supports for displacing a memberof the transformer to control current in the said conductor, and meanscarried'by one of said supports for operating a valve for projectingquenching fluid onto a face or the article 16. In apparatus of thecharacter described, a conductor extending around an article to be heattreated, means for progressively moving the article thru the conductor,the said conductor serving as means for causing heating current to flowin a surface of the article, and means for controlling the heatingcurrent, said last named means comprising a regulating a generator, anaxially movable cam, the rotating cam being geared to said axiallymoving cam, and the axially moving cam regulating a space between theconductor and the article.

17. In apparatus of the character described, a heater extending aroundan article to be heat treated, and means for progressively moving saidarticle thru said heater, said means comprising a threaded shaft, anexternally threaded nut receiving the shaft, and means for limiting amovement of the shaft in the nut whereby the nut is caused to rotate andchange the rate of the progressive movement of the article thru theheater.

18. In apparatus of the character described, a conductor extendingaround an article to be heat treated, means for progressively moving thearticle thru the conductor,' said means comprising a rotating threadedshaft supporting the article, an operating arm moving longitudinallywith the article, a transformer supplying current to the conductor, saidtransformer having relatively moveable members, and means whereby theoperating arm moves a member of the transformer to control current inthe said conductor.

19. In apparatus of the character described, a conductor extendingaround an article to be heat treated, means for progressively moving thearticle thru the conductor, said means comprising a traveling supportfor the article, a longitudinally extending arbor being attached to' thesupport and moving therewith, said arbor having a cam, the said camengaging a part of the conductor for varying the position of theconductor relative to an axis of the article, and means for controllingcurrent in the conductor.

20. In apparatus of the character described, a conductor extendingaround an article to be heat treated, a threaded shaft being attached tothe article and serving as means for moving the article thru theconductor, an externally threadednut engaging the shaft and serving as asupport therefor, and braking means for resisting a movement of the nutwhereby the nut is prevented from rotating with said shaft until thearticle has reached a predetermined position.

21. In a device for heat-treating, a substantially annularhigh-frequency current conductor serving as a heating element andembracing part of an article to be heat-treated, means for progressivelychanging the form of the conductor to vary the flux field set upthereby, quenching passages in the conductor, and means for causingsubstantially continuous relative axial movement between said articleand said heating element during a heating interval.

22. In a device for heat-treating, a conductor in heating relationshipwith an article to be heat-treated, said conductor comprising elementsshiftable to occupy varying relative positions, means for causingrelative movement between said elements and said article, guiding meansadapted to maintain spaced relationship between said elements and saidarticle, and means for varying the form of said conductor, said meansfor varying the form of the conductor rotating cam for a I ductor, meansto vary the being controlled by the relative movement between saidelements and said article.

23. In a device for heat-treating, a conductor adapted to lie in heatingrelationship with an article of a varying form to be heated, means forchanging the position of said conductor relative to said article duringthe heating interval, said means being automatically actuated byrelative movement of a member with a form corresponding to the varyingform of said article.

24. In apparatus of the character described, a high-frequency conductoradapted to peripherally embrace an article to be heat-treated, a supportfor said article, means for producing relative movement between saidarticle and said conductor, a source of high-frequency current leadingto said conductor, and control mechanism actuated by movement of thearticle and the conductor with respect to each other to vary both thesaid rate of movement and the amount of current fed to said conductor.

25. In apparatus of the character described, a variable conductoradapted to peripherally embrace an article to be heat-treated, means tosupply electrical energy to said conductor to set up a flux field ofpre-determined value, active on the entire zone embraced, a support foran article to be heat-treated by induction due to said flux field,mechanism operable to pass said article progressively through the fluxfield at a variable rate of speed, and means to automatically controlthe value of the flux field by varying the form of the embracingconductor and further varying the speed of movement of the article andthe fiux field with respect to each other in accord with a predeterminedratio.

26. In apparatus of the character described, a conductor adapted toclosely approach an article to be heat-treated, a source ofhigh-frequency current to establish a flux field to heat said article,means to supply the current to said constrength of the fiux field insaid article, a support for the article to be acted on by saidconductor, mechanism to cause the supported article and the conductor tomove with respect to each other, means to vary the rate of saidmovement, and control mechanism to automatically vary the flux value andthe said rate of movement in a pre-determined manner.

27. Apparatus for heat-treating an article with a projecting shouldercomprising an inductive electric heating element adapted to encirclesaid article, mechanism to progressively pass part of the body portionin proximity to said element to heat part of said body, fluid quenchingmeans adjacent said element to quench a progressively heated bodyportion of the article, and means to stop or retard the relativemovement between the article and the heating element adjacent saidshoulder to heat and quench a zone adjacent the shoulder during saidstopped or retarded relative movement between the article and theheating element.

28. In apparatus of the character described, a conductor of variableform extending peripherally around an article to be heat-treated, a camfor controlling the form thereof, means for progressively advancing thearticle through the conductor, and means for regulating current inducedin a surface zone of the article whereby heating of the said zone iscontrolled, said means comprising a field circuit control cam havinggeared connection with the cam controlling the form of the conductor.

w mauve m'im ammary with fie fm 0E; m each mmer m cmtml the current;deiivexed in said fimlmmr.

EWRANCIES S. DENNEEN.

C. DUNN. 6

